In order to meet the growth in wireless data traffic demand since the commercialization of 4th Generation (4G) communication systems, many studies have been conducted to develop an enhanced 5G or pre-5G communication system. For this reason, the 5G or pre-5G communication system is also called a beyond-4G communication system or a post Long Term Evolution (LTE) system.
Consideration is being given to implementing the 5G communication system in millimeter wave (mm Wave) frequency bands (e.g., 28 GHz and 60 GHz bands) to accomplish higher data rates. In order to increase the propagation distance by mitigating propagation loss in the 5G communication systems, discussions are underway about various techniques such as beamforming, massive MIMO, Full Dimensional MIMO (FD-MIMO), array antenna, analog beamforming, and large scale antenna.
Also, in order to enhance network performance of the 5G communication systems, development is underway of various techniques such as evolved small cell, advanced small cell, cloud Radio Access Network (RAN), ultra-dense network, Device to Device (D2D) communication, wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation.